Analysts warn huge hydroelectric project in Tibet could risk geological disasters and irk New Delhi as neighbours try to ease tensions Beijing's approval of a controversial mega dam in the lower reaches of the Yarlung Tsangpo River,

The total cost of the dam could go beyond 1 trillion yuan (about $137 billion), making it the most expensive infrastructure project ever built in the world.

China has approved the construction of what will be the world's largest hydropower dam, kicking off an ambitious project on the eastern rim of the Tibetan plateau that could affect millions downstream in India and Bangladesh.